Conflicting results exist in the literature on the effects of drugs on driving. This is a major concern as 9.9 million persons reported driving under the influence of illicit drugs in 2013. The Fatality Analysis Reporting System (FARS), a census of all U.S. fatal vehicle crashes, is a source of information that could shed light into this discrepancy. However, currently it is not possible to determine tests performed as FARS only records positive and not negative results. This gap is a major impediment to understanding the impact of drugs and driving. FARS also does not distinguish between the active THC, responsible for the acute effects of marijuana, and the inactive metabolites, which can persist for weeks. Therefore, we do not know if fatally injured drivers were under the influence of marijuana at the time of the crash or if the consumption occurred days prior the crash. These deficiencies preclude conducting studies evaluating drug involvement in crashes, trends, or the effects of drugged driving laws. Comprehensive and high quality data on fatally injured drivers exists in certain states with centralized forensic laboratories. The current structure of FARS does not utilize this information as no mechanism is in place to link these reporting systems. The long-term objective of this study is to reduce drug related traffic injuries by developing a reliable databas using toxicology data that can support valid drugged driving research. The main aim of this R21 exploratory grant is to demonstrate the feasibility of developing a sentinel Drug-FARS research database to investigate important issues regarding drugs and traffic crash risk. Subsequent aims include determining the prevalence and trends in drug involvement in fatally injured drivers; and identifying potential states and counties for development of a comprehensive Drug-FARS for future research. This study is an innovative, cost-effective, and sustainable application of data linkage of medical examiner, toxicology, and FARS databases to address the public health need for data on drug use and driving. A multi-disciplinary Expert Working Group will advise on the development of a toxicology database model for traffic fatalities. Toxicology laboratory and medical examiner data from three states, Maryland, Washington, and West Virginia will be examined and data harmonized into common data elements. Linkage of toxicology data with FARS at the state level will enrich the quality data on crash circumstances and contributing factors. The database will be used to determine accurate drugged driving prevalence and trends. In-depth analyses of drugs testing in FARS will also be conducted to identify candidate states for development of a comprehensive Drug-FARS. This research will result in a research database (Sentinel Drug-FARS) that will enable researchers to determine risks related to individual drugs and driving, and to design, monitor and evaluate interventions targeting drugged driving. The fulfillment of the aims will potentially influence the core toxicoloy drug data collection and linkage methodology from the local to the national levels. This study will also contribute to standardize the data process to facilitate comparison across states and time.